Device for opening connection to lined pipe

ABSTRACT

A device for opening a connection to a lined pipe is disclosed. The device has a body that includes a front end and a rear end and being rotatable about a rotation axis. The device also has a drill head that has multiple cutters for puncturing and enlarging a hole in a liner, and multiple side cutters have at least one cutting edge parallel to the rotation axis. A safety ring is disposed on the body between the drill head and the side cutters. The safety ring has a circular periphery extending beyond the drill head and the side cutters in a direction perpendicular to the rotation axis.

FIELD OF THE INVENTION

The present invention relates to pipe renovation tools and in particularto a device for opening a connection to a lined pipe.

BACKGROUND AND SUMMARY OF THE INVENTION

Pipes, such as water and sewage pipes, approaching the end of theirservice life may be renovated e.g. by lining or coating the inside of anold pipe or by mounting a new pipe into an old pipe. An epoxyresin-impregnated polyester liner, for example, that is inverted into apipe to be renovated using compressed air or water can be used inlining. After inversion of the liner into the pipe, excess pressure ismaintained inside the liner until the epoxy resin cures to its shapeconforming to the walls of the old pipe. Modern technology allows evenhighly complex pipes to be lined.

One of the problems with solutions of the prior art is reinstatingconnections in a pipeline when a pipe of the pipeline has been lined.The liner typically covers the whole inner surface of the old pipe thatwas lined and blocks all connections, e.g. from lateral pipes to a linedmain pipe. Typically, these connections are opened with a robot cutterthat is transported in to the main line and operated manually. A cameraof the robot is used for finding the lateral connection and a cuttinghead is operated to cut the liner blocking the connection whilemonitoring the process with the camera. This method is slow and riskybecause an operator of the robot can accidentally hit the liner with thecutting head outside of the connection and expose the old pipe behindthe liner. The use of the robot cutter also requires that the main pipewhere the robot operates is large enough and straight enough because therobots are bulky and cannot move through tight bends in the pipe.

It is an object of the present invention to present a device that allowssafer and/or faster opening of a connection to a lined pipe than theprior art solutions.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, the present invention is described in greater detailby means of preferred embodiments with reference to the accompanyingdrawings, in which

FIG. 1 shows an isometric presentation of a device according to anembodiment of the present invention;

FIG. 2 shows a device according to an embodiment of the presentinvention from a direction normal to a rotation axis of the device;

FIG. 3 shows a device according to an embodiment of the presentinvention in a direction of the rotation axis; and

FIG. 4 shows a device according to an embodiment of the presentinvention in a pipeline.

DETAILED DESCRIPTION OF THE INVENTION

Renovation of pipelines in buildings, such as residential buildings,offices and industrial plants, using CIPP (Cured In-Place Pipe) pipelining method has become common in recent years. The CIPP industry hasevolved from leak repairs where a short piece of liner was installed torepair a leaking part of an existing pipe to lining of main lines onlyto full renovations where every pipe and connection is lined creating acomplete new pipeline inside the existing old pipeline. A fullrenovation requires lining of pipes in various sizes, usually throughmultiple bends and including a lot of connections.

FIG. 1 shows a device 50 according to an embodiment of the presentinvention for opening a connection to a lined pipe. FIG. 2 and FIG. 3show the device from different angles. FIG. 4 shows an example of wherethe device can be used by placing the device in a lateral pipe 100. Thelateral pipe 100 connects to a main pipe 200 which is lined with a liner220. The device 50 is attached to a flexible rotation shaft 40 andpushed with the shaft 40, through the lateral line 100, towards theliner 220 of the main pipe 200 for opening a connection from the lateralpipe 100 to the main pipe 200.

The device 50 of the embodiment in FIG. 1 has a body rotatable about arotation axis RA and has a front end and a rear end opposite to thefront end. A shaft socket is provided on the rear end of the device. Theshaft socket may have a cavity or a hole defined therein foraccommodating or receiving a shaft 40 and threaded holes 12 through thebody into said cavity or said hole. Preferably, the shaft 40 is pushedinto the cavity or hole and secured with screws through the threadedholes 12. Once the shaft 40 is secured to the device 50, rotation of theshaft 40 rotates the device 50.

A drill head 32 is provided at the front end of the body and the drillhead has multiple cutters for puncturing and enlarging a hole in theliner 220. The drill head 32 at the front end of the body preferably hasfour step-wise tapered cutters. Each of these cutters has multiplecutting edges 34 parallel to the rotation axis and multiple cuttingedges 34 perpendicular to the rotation axis. The step-wise taperedconstruction of the drill head 32 punctures a hole and enlarges thepunctured hole step-by-step thereby reducing torsional forces to theshaft compared to a drill head with a larger contact area. The deviceenlarges the hole to a size (diameter) larger than the diameter of thedrill head because the sharp-edged front drill head bounces around theedges of the hole chipping away the liner instead of drilling smoothly.Spacers 30 can be disposed between adjacent cutters of the drill head 32to prevent the drill head from cutting too deep which could cause excessbouncing of the device or jamming of the device. The spacers 30 fill thespace between the cutters of the drill head 32 thereby limiting amaximum cutting depth to a distance between the spacer and a cuttingedge 34 of the cutter.

The device also has multiple side cutters 16 on the peripheral surfacesof the body between the front end and the back end. Each of the sidecutters 16 has at least one cutting edge 14 that extends along the bodyand parallel to the rotation axis RA. After puncturing a hole to theliner 220 with the drill head and enlarging it with the drill head tofit the device 50 through the hole, the side cutters 16 are, preferably,used to cut away the rest of the liner blocking the connection. Whenrotating the device halfway through the hole in the liner, the devicebounces around the hole and the side cutters 16 chip away the rest ofthe liner until diameter of the hole matches diameter of the lateralpipe 100, i.e. the connection is fully opened to the main pipe 200.Preferably, each side cutter 16 has one or two right-angled cuttingedges 14 parallel to the rotation axis RA. Spacers 18 can be disposedbetween adjacent side cutters 16 to prevent the side cutters 16 fromcutting too deep which could cause excess bouncing of the device orjamming of the device. The spacers 18 fill the space between the sidecutters 16 thereby limiting a maximum cutting depth to a distancebetween the spacer 18 and a cutting edge 14 of the side cutter 16.

The device 50 has a safety ring 20 disposed on a round peripheralsurface of the the body between the drill head 32 and the side cutters16. The safety ring 20 is preferably an integral part of the body andthe safety ring 20 has a circular periphery extending beyond the drillhead 32 and the side cutters 16 in a direction perpendicular to therotation axis. In other words, the safety ring 20 has a larger diameterthan any other part on the body and extends radially outwardly from thebody. The circular peripheral outer surface of the safety ring 20 issmooth so it does not cause or amplify the bouncing of the device in apipe. On straight sections of the pipe, preceding a connection area inthe pipe, only the safety ring 20 and possibly also the chamfered rearend 10 of the device can be in contact with the inner surface of thepipe. Preferably, the rear end 10 is tapered and also the safety ring 20has one or two short tapered or chamfered sections 19, 21 on one or bothannular edges and a flat section parallel to the rotation axis in themiddle, i.e. between said tapered sections 19, 21. Since these smooth,annular and preferably tapered sections, i.e. the rear end 10 and thesafety ring 20, of the device 50 are the only parts in contact with theinner surface of the pipe, the device 50 is safe to use even in plasticpipes, such as PVC and PE pipes. The device can also be used in a pipethat has already been lined because the installed liner will not bedamaged. The design of the device to include the safety ring 20 betweenthe side cutters 16 and cutters of the drill head 32 prevents anycutting edges from accidentally contacting the inner surface of thepipe. The cutting edges 14, 34 only make contact with a liner of themain pipe 200 in a connection area where the liner is blocking thelateral pipe 100 from where the connection between the two pipes can beopened with the device 50.

It is surprisingly easy to drill a hole in a liner by using the deviceof the present invention and to push the safety ring through the hole inthe liner even though it looks like a challenging task based on theappearance of the device. The safety ring can be designed so that it islarge enough to ensure that the lateral pipe 100 itself is not damagedby the device but still the device can be quickly and easily drilledthrough the liner at the end of the lateral pipe so that the safety ringis disposed inside the main pipe 200. Also, the device can besignificantly smaller in diameter than the lateral pipe 100 in which thedevice operates. Thereby, it is easy to navigate to the connection areaof the lateral pipe 100 and the main pipe 200 even through multipletight bends in the lateral pipe by simply pushing the device 50 forwardin the lateral pipe with the rotation shaft 40. Even though the deviceis smaller in diameter than the inner diameter of the lateral pipe andthe hole needed in the liner, the side cutters 16 quickly enlarge thehole in the liner to the desired size without a risk of removing toomuch of the liner. The small tapered sections 19, 21 of the safety ring20 facilitate the pushing of the device through the initial hole made bythe drill head 32 and also the pulling of the device back through thefully opened connection so that the safety ring is again in the lateralpipe 100.

The device, i.e. an entity of the body, the side cutters 16, the safetyring 20 and the drill head 32, is preferably machined from a singlepiece or cast as a single piece and preferably annealed to reducedulling of the cutting edges 14, 34. Preferably, the device is made ofsteel and annealed.

The number of the cutters of the drill head 32 may be other than fourand it is also possible to use a device that has one, two, three, five,six or eight cutters. As a rule of thumb, the larger the device, themore cutters may be needed for optimal performance. If necessary, evenmore cutters may be used. The same applies to the side cutters 16.However, four drill head cutters and four side cutters has been found toperform well in e.g. 100 mm/4 inch pipes.

The rotation shaft 40 used with the device is a rotation shaft that isflexible but stiff in thrust, such as a steel cable. The rotation shaftis, preferably, provided with a cover tube at least partly surroundingit, the cover tube is not fastened to the rotation shaft so as to allowtaking a hold of the cover tube and so that it does not revolve as therotation shaft rotates. The cover tube allows the rotation shaft and thedevice fastened to an end thereof to be guided in the pipe in a desiredmanner. The rotation shaft can be rotated with e.g. electric, hydraulicor pneumatic motor.

FIG. 4 shows a device according to an embodiment in a lateral pipe fromwhich the device may be used to open a connection to a main pipe 200 byremoving a piece of the liner 220 from the connection area. The lateralpipe has an inner diameter substantially greater than the outer diameterof the device. The diameter of the device may be understood to refer tothe greatest dimension perpendicular to the rotation axis RA, i.e. theouter diameter of the safety ring 20. The length of the device may beunderstood to refer to the greatest length in the direction of therotation axis, i.e. the length from the rear end of the device to thetip of the drill head in the front end of the device. The dimensioningof the device in relation to the size of the pipe to be milled affectsthe behavior of the device in the pipe. For the device to rotate in apipe without damaging the pipe itself, the diameter and length of thedevice should be in specific proportions to one another and to the innerdiameter of the pipe. Also, equally important is the diameter of thesafety ring vs. maximum distance between two cutting edges 34 of thedrill head 32 and/or maximum distance between two cutting edges 14 ofthe side cutters 16.

It has been observed that a preferred diameter of the device is 40 to70% of the inner diameter of the pipe and particularly preferably thedevice diameter is 50 to 60% of the inner diameter of the pipe. Apreferred length of the device is 70 to 200% of the inner diameter ofthe pipe and particularly preferably the device length is 80 to 150% ofthe inner diameter of the pipe. A preferred diameter of the device is atleast 30% of the length of the device and particularly preferably thediameter of the device is at least 40% of the length of the device. Apreferred diameter of the device is at most 80% of the length of thedevice and particularly preferably the diameter of the device is at most70% of the length of the device. For example, a device fitting into apipe having an inner diameter of 100 mm might have e.g. a diameter of 55mm and a length of 100 mm.

Preferably, the safety ring 20 extends at least 5% further away from therotation axis RA than any cutting edge 14, 34 in a directionperpendicular to the rotation axis, i.e. the safety ring 20 has a radiusthat is at least 5% greater than the radius of the cutting edges 14, 34.In an embodiment, the safety ring 20 can extend at least 2%, at least8%, at least 10% or from 2% to 10% further away from the rotation axisthan any cutting edge 14, 34 in a direction normal to the rotation axis.

Regardless of the ratio between distances of cutting edges and safetyring from the rotation axis, the safety ring extends or protrudes atleast 1 millimeter further away from the rotation axis RA than anycutting edge in a direction perpendicular to the rotation axis, i.e. thesafety ring 20 has a radius that is at least 1 mm greater than theradius of the cutting edges 14, 34. In an embodiment, the safety ringcan extend at least 2 mm, at least 3 mm, at least 5 mm or from 1 mm to 5mm further away from the rotation axis RA than any cutting edge in adirection normal to the rotation axis.

In addition to the dimensions of the device, also the stiffness of therotation shaft 40 used has an essential influence on an optimal diameterand length of the device. Therefore, the proportions given may differfor specific rotation shafts from those disclosed here. The ratio of thediameter and length of the device to the inner diameter of the pipe inwhich the device operates, together with the stiffness of the rotationshaft, should provide safe operation in which the cutting edges of thedevice is unable hit the pipe walls in a straight segment of the pipe soas to maintain the pipe substantially undamaged to allow renovation bylining also the lateral pipe to be carried out. In addition, the deviceshould be able to advance in the bends of the pipe without substantiallydamaging the pipe itself even at a bend of the pipe to be relined.

It is apparent to a person skilled in the art that the above exemplaryembodiments are rather simple in structure and operation for thepurposes of illustration. By following the model shown in this patentapplication, it is possible to construct different and even very complexsolutions that utilize the inventive idea disclosed in this patentapplication.

1. A device for opening a connection to a lined pipe, comprising: a bodyhaving a front end and a rear end opposite to the front end and beingrotatable about a rotation axis, a drill head at the front end of thebody, the drill head comprising multiple cutters for puncturing andenlarging a hole in a liner, multiple side cutters on the body disposedbetween the front end and the rear end, each side cutter having at leastone cutting edge parallel to the rotation axis, a safety ring disposedon the body between said drill head and said side cutters, the safetyring having a circular peripheral surface extending beyond said drillhead and said side cutters in a direction perpendicular to the rotationaxis; the drill head at the front end of the body having four step-wisetapered cutters, each of the cutters having multiple cutting edgesparallel to the rotation axis and multiple cutting edges perpendicularto the rotation axis; and spacers being disposed between adjacentcutters of the drill head for reducing cutting depth of the cutters.2-3. (canceled)
 4. A device as claimed in claim 1, wherein the safetyring extends at least 5% further away from the rotation axis than anycutting edge in a direction perpendicular to the rotation axis.
 5. Adevice as claimed in claim 1, wherein the safety ring extends at least 1millimeter further away from the rotation axis than any cutting edge ina direction normal to the rotation axis.
 6. A device as claimed in claim1, wherein the safety ring has a tapered section towards the rear end ofthe body and a tapered section towards the front end of the body.
 7. Adevice as claimed in claim 6, wherein the safety ring has a flat sectionparallel to the rotation axis between said tapered sections. 8.(canceled)
 9. A device for opening a connection to a lined pipe,comprising: a body having a front end and a rear end opposite to thefront end and being rotatable about a rotation axis, a drill head at thefront end of the body, the drill head comprising multiple cutters forpuncturing and enlarging a hole in a liner, multiple side cutters on thebody disposed between the front end and the rear end, each side cutterhaving at least one cutting edge parallel to the rotation axis, a safetyring disposed on the body between said drill head and said side cutters,the safety ring having a circular peripheral surface extending beyondsaid drill head and said side cutters in a direction perpendicular tothe rotation axis; wherein there are four side cutters at the front endof the body, each side cutter having one or two right-angled cuttingedges parallel to the rotation axis; and spacers being disposed betweenadjacent side cutters for reducing cutting depth of the side cutters.